1. Field of the Invention
The present invention is broadly concerned with improved headsets for aircraft crew members which are comfortable to wear and include shiftable mask and visor units which can be automatically or manually moved from a retracted position over the crown of the wearer's head to lowered, deployed positions. In this way, little or no crew member effort is required in emergency situations such as flight deck depressurization or smoke in the flight deck, so that the crew may very rapidly receive breathable gas and have eye protection.
2. Description of the Prior Art
Pursuant to government regulations, passenger aircraft flight decks are provided with emergency oxygen equipment which is used by the air crew in the event of an emergency such as a depressurization or smoke in the flight deck. Such equipment generally includes a mask (either full-face or covering the nose and mouth region of a wearer) which is stowed adjacent the crew member. When an emergency occurs, the mask is grasped, pulled from stowage and donned by the crew member. The mask is coupled with an oxygen supply hose so that emergency oxygen, or an air-oxygen mixture, is delivered to the mask. Typically, emergency masks of this type must be capable of being donned within five seconds.
U.S. Pat. No. 4,915,106 describes a crew oxygen mask having an inflatable harness. That is, when the mask is pulled from stowage, the harness straps are inflated and assume a substantially enlarged configuration allowing the mask assembly to be rapidly placed over the user's head. Thereupon, a valve mechanism is actuated to deflate the harness straps so that the harness tightens and securely holds the mask in place. The '106 patent further describes a comfort control feature allowing the crew member to adjust the effective tension of the harness straps. U.S. Pat. No. 3,599,636 discloses a similar harness-inflation mask assembly.
While these types of crew oxygen masks can permit rapid mask donning, the crew member must find the mask, pull it out of stowage and put it on before the emergency can be addressed. Depending upon aircraft altitude, a slow response on the part of the crew member or failure to recognize oxygen depletion can lead to catastrophic results. Moreover, inflatable harness masks require a rather large and bulky stowage device and related equipment, which must be situated in relatively close proximity to each crew member. This takes up valuable space within the already-crowded crew flight deck, and moreover increases aircraft weight. Finally, in large commercial aircraft the oxygen hoses associated with conventional masks have become rather long, which again dictates that the stowage device must be of considerable size.
Another hazard sometimes encountered in the flight deck is the presence of smoke, which may result from an electrical fire or the like. While existing crew oxygen equipment supplies breathable gas to the crew members during smoky conditions, the presence of smoke can cause irritation to the eyes (if a half face mask is worn) or significantly obscure the crew member's vision. In light of this problem, a number of visors or other eye protective devices have been proposed. However, in many cases the supplemental smoke-protection equipment takes up still further valuable deck space and requires additional donning time. In large commercial aircraft, there are multiple locations of stowed equipment which may result in the equipment being misplaced, lost, stolen or damaged.
There is accordingly a need in the art for improved air crew emergency oxygen and smoke protection equipment which eliminates the need for separate stowage devices and long supplemental oxygen hoses typical of inflatable-harness masks, but which retain the ability to be deployed in a very rapid fashion during flight deck emergencies.